Note that similar to the previous work [1]}, [2]}, we focus on a fundamental real channel scenario, i.e., \(h_k,b_k,y_t,z_t \in \mathbb {R},\forall k \in \mathcal {K}\) ,
though the analytical framework and results in the paper can be readily
extended to the complex channel scenario by representing \(y_t\)  and \(z_t\)  as two-dimensional vectors, and \(\mathbf {b}\)  as a \(K\times 2\)  matrix with real and imaginary parts.
